# # Program information file # PROGRAM_ID 2022A009 PROGRAM_TITLE Thermal mapping of SO2 and HDO at the cloud top of Venus PROGRAM_INV1 Therese Encrenaz PROGRAM_INV2 Thomas Greathouse PROGRAM_INV3 Rohini Giles PROGRAM_INV4 Emmanuel Marcq PROGRAM_INV5 Thomas Widemann PROGRAM_SCICAT major planets / satellites PROGRAM_ABSTRACT_BEG We propose to use TEXES to study spatial and temporal variations of SO2 and H2O [through its proxy HDO] in the atmosphere of Venus over and within the clouds. Since 2012, maps of SO2 and HDO have been repeatedly recorded at 7 and 19 microns to search for short-term and long-term temporal variations. These data have shown that the disk-integrated abundance of SO2 atop the clouds has significantly changed over this time period, by a factor up to 10. They have also shown evidence for a long-term anticorrelation between SO2 and H2O, which has been analyzed through GCM photochemical models. In addition, the data show that SO2 plumes appear and disappear at the cloud top with a lifetime of a few hours. We propose to continue this campaign with the following objectives: [1] to obtain a reliable value of the disk-integrated SO2 content during the first semester of 2022; [2] to improve the statistics about the distribution of the SO2 plumes as a function of local time [which requires one measurement per day]; [3] to further constrain the lifetime and evolution of the SO2 plumes. In addition, [4] we plan to search for SO2 at 8.6 microns in a spectral range which probes a region located above the clouds, in order to better constrain the SO2 vertical profile within and above the clouds. Finally, we plan to compare our observations with UV observations of SO2 with the Akatsuki probe. PROGRAM_ABSTRACT_END